4 files changed, 224 insertions, 0 deletions

diff --git a/day08/input b/day08/input
new file mode 100644
index 0000000..ffdd5b1
--- /dev/null
+++ b/day08/input
@@ -0,0 +1,99 @@
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diff --git a/day08/part1.rb b/day08/part1.rb
new file mode 100644
index 0000000..7bd78ad
--- /dev/null
+++ b/day08/part1.rb
@@ -0,0 +1,56 @@
+def check_up(grid, ri, ci)
+  tree = grid[ri][ci]
+  loop do
+    ri -= 1
+    break if ri < 0
+    return false unless grid[ri][ci] < tree
+  end
+  true
+end
+
+def check_down(grid, ri, ci)
+  tree = grid[ri][ci]
+  loop do
+    ri += 1
+    break if ri >= grid.count
+    return false unless grid[ri][ci] < tree
+  end
+  true
+end
+
+def check_left(grid, ri, ci)
+  tree = grid[ri][ci]
+  loop do
+    ci -= 1
+    break if ci < 0
+    return false unless grid[ri][ci] < tree
+  end
+  true
+end
+
+def check_right(grid, ri, ci)
+  tree = grid[ri][ci]
+  loop do
+    ci += 1
+    break if ci >= grid[ri].count
+    return false unless grid[ri][ci] < tree
+  end
+  true
+end
+
+grid = $stdin.readlines.map(&:strip).map(&:chars).map { |row| row.map(&:to_i) }
+
+num_visible = 0
+
+grid.count.times do |ri|
+  grid[ri].count.times do |ci|
+    visible = false
+    visible = true if check_up(grid, ri, ci)
+    visible = true if check_down(grid, ri, ci)
+    visible = true if check_left(grid, ri, ci)
+    visible = true if check_right(grid, ri, ci)
+    num_visible += 1 if visible
+  end
+end
+
+puts num_visible
diff --git a/day08/part2.rb b/day08/part2.rb
new file mode 100644
index 0000000..fa4a61c
--- /dev/null
+++ b/day08/part2.rb
@@ -0,0 +1,64 @@
+def score_up(grid, ri, ci)
+  tree = grid[ri][ci]
+  vis = 0
+  loop do
+    ri -= 1
+    break if ri < 0
+    vis += 1
+    break if grid[ri][ci] >= tree
+  end
+  vis
+end
+
+def score_down(grid, ri, ci)
+  tree = grid[ri][ci]
+  vis = 0
+  loop do
+    ri += 1
+    break if ri >= grid.count
+    vis += 1
+    break if grid[ri][ci] >= tree
+  end
+  vis
+end
+
+def score_left(grid, ri, ci)
+  tree = grid[ri][ci]
+  vis = 0
+  loop do
+    ci -= 1
+    break if ci < 0
+    vis += 1
+    break if grid[ri][ci] >= tree
+  end
+  vis
+end
+
+def score_right(grid, ri, ci)
+  tree = grid[ri][ci]
+  vis = 0
+  loop do
+    ci += 1
+    break if ci >= grid[ri].count
+    vis += 1
+    break if grid[ri][ci] >= tree
+  end
+  vis
+end
+
+grid = $stdin.readlines.map(&:strip).map(&:chars).map { |row| row.map(&:to_i) }
+
+max_score = 0
+
+grid.count.times do |ri|
+  grid[ri].count.times do |ci|
+    score = 1
+    score *= score_up(grid, ri, ci)
+    score *= score_down(grid, ri, ci)
+    score *= score_left(grid, ri, ci)
+    score *= score_right(grid, ri, ci)
+    max_score = score if score > max_score
+  end
+end
+
+puts max_score
diff --git a/day08/test b/day08/test
new file mode 100644
index 0000000..16d6fbd
--- /dev/null
+++ b/day08/test
@@ -0,0 +1,5 @@
+30373
+25512
+65332
+33549
+35390